public class ShapeManager{
    private static final int MAX_NUM = 100;
    private Shape[] shapes= new Shape[MAX_NUM];
    private int shapeNum = 0;
    public void addShape(Shape shape){
        if(shapeNum<MAX_NUM){
            shapes[shapeNum++] = shape;
        }
    }
    public void draw(){
        for(int i=0; i<shapeNum; i++){
            shapes[i].draw();
        }
    }
}